In the television version, this segment starts with Ernie telling Bert that he can't sleep because he is scared of monsters; not friendly monsters like the ones he knows, but scarier monsters who hide in the dark and go "wubba, wubba." Bert tells Ernie to imagine some things that he is not afraid of (primarily balloons of different sizes), and the pair sing the song.

An unaired version of this song was taped, referred to internally by the Workshop as "Monster Opera." In the extended, ten-minute segment, Ernie's good night sleep is roused by the sounds of a cat and a dog nearby and wakes up Bert as a result, who tries to quell Ernie's fears. Ernie's imagination begins to run away with him, as he imagines the street populated with scary monsters (who are depicted as transparent to convey being imaginary) that sing a brief, chilling song. Frightened, Ernie wakes up Bert again and sings a song about his fear (howling "Go away, bad things, go away!") as he imagines the monsters invading their bedroom. Bert convinces him to imagine pleasant things instead as he launches into "Imagination."[1] Tests with child audiences showed that children paid more attention to Ernie's fear than to the song itself, so the intended message was not fully comprehended. The prologue was subsequently omitted and the entire segment reworked.[2] A new, shorter prologue was produced and woven into footage of the original version. Behind the scenes photos of the unaired version can be seen in issue #20 of the magazine KIDS.